The security officials said around 90 people were wounded in the blast that took place Wednesday morning.[break]
The attack was the latest in a string of bombings this week that have targeted pilgrims making their way to an important Shiite religious observance in Karbala.
The blasts have raised fears of a spike by suspected Sunni insurgents in attacks when the pilgrimage culminates Friday.
The officials spoke on condition of anonymity because they were not authorized to brief the media.
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